Auxiliary detonator fuze for antiaircraft projectile



June 5, 1956 R, GRAUMANN 2,748,707

AUXILIARY DETONATOR FUZE FDR ANTI-AIRCRAFT PROJECTILE Filed June 25,1945 2 Sheets-Sheet 2 I l 4e 37 47 45 e7 737172 46 7o 36 68: 1 768 7| iglwuc/wm 53 54 58 @WMM/MM United States Patent M' AUXILIARY DETONATORFUZE FOR ANTI- AIRCRAFT PRGJECTILE Raymond L. Graumann, Alexandria, Va.

Application June 23, 1945, Serial No. 601,285

3 Claims. (Cl. 102--79) (Granted under Title 35, U. S. Code (1952), sec.266) This invention relates to a safety auxiliary fuze for a projectileand more particularly to a fuze for use with a projectile employing theusual time delay nose fuze and known to those skilled in art as ananti-aircraft or highexplosive projectile and used by the armed forcesfor the purpose of destroying enemy aircraft and the like. Moreespecially this invention relates to a safety auxiliary fuze for an4anti-aircraft projectile adapted to be fired from a gun and providedwith means adapted to explode an explosive charge within the projectilein predetermined time delayed relation with respect to the firing of theprojectile from a gun in which contact with a target is not necessary tofire the charge, The invention relates to an auxiliary fuze for aprojectile in which the firing pin and detonator are maintained in asafe position with respect to each other and will remain in safeposition vuntil the projectile has attained a predetermined speed ofrotation after the projectile has been fired from a gun, and until theforce of acceleration of the projectile has diminished to a valuecorresponding to the force of acceleration acting on the projectile at asafe distance from the gun after the projectile has been tiredtherefrom.

One of the objects of the present invention is the provision of a newand improved means for preventing the premature firing of an explosivecharge within a projectile during the transportation, handling, loadingand firing of the projectile from a gun.

-Another of the objects `is to provide a new and irnproved device forpreventing the premature ring of an explosive charge within a projectilein which means are provided for maintaining a rotatable detonator insafe position and in which a slideable ring pin is locked in s afeposition until the velocity of the projectile has reached substantiallythe maximum value after the projectile has been red from a gun.

lA further object is to provide a new and improved device formaintaining a rotatable detonator and tiring pin of a projectile in asafe or unarmed position until the vprojectile has passed beyond themuzzle of a gun, whereupon the rotatable detonator will be actuated to atiring position and a lock be removed from the firing pin under theinuence of centrifugal force.

A still further object of the invention is to provide new and improvedmeans for a projectile for maintaining the rotatable detonator and theslideable tiring pin of a projectile in a safe position until theprojectile is shot clear ofthe gun which is reliable in operation, andwhich possesses all of the desired qualities of safety and durability.

Still other objects and advantages will be apparent from the followingdescription taken in connection with the .accompanying drawings, ofwhich: Fig. 1 is a sectional View of a high-explosive time delayprojectile employing the auxiliary fuze of the present inventionaccording to a preferred'embodiment thereof; y Fig, 2 ifs an enlargedsectional view of the auxiliary fuzeconstructedin accordance with thepresent invention;

Z ,748 ,707 Patented 'June 5, 1956 Fig. 3 is an end elevational view ofthe auxiliary fuze;

Fig. 4 is a sectional view of the auxiliary fuze similar to Fig. 2 butshowing the device in an armed condition;

Fig. 5 is a sectional View of the fuze taken on line 5 5 of Fig. 4;

Fig. 6 is a sectional View of the fuze taken on line 6 6 of Fig. 4;

Fig. 7 is a face view of the rotor supporting the detonator;

Fig. 8 is an edge view of the rotor and detonator; and,

Fig. 9 is a fragmentary sectional view showing the rotor in an unarmedcondition.

Referring now to the drawings for a more complete understanding of theinvention and more particularly to Fig. l thereof, there is shownthereon a projectile indicated generally by the numeral 10 having anannular groove 11 therein adapted to engage a complementary portion of acartridge case i2 to which the projectile is secured, as is well knownin the art to which the present invention pertains. The projectile isalso provided with an annular sleeve 13 of material suitable for thepurpose such, for example, as copper adapted to be engaged by the riingof the gun as the projectile is propelled outwardly therefrom by theexplosion of the explosive charge 14 arranged within the cartridge case12 and thereby impart rotary movement to the projectile about the axisthereof as the projectile moves through thebore of the gun. Theprojectile is thus adapted to be propelled along a predeterminedtrajectory and to spin or rotate continuously about its axis throughoutthe trajectory as the result of the rotary movement imparted thereto bythe riing of the gun.

The projectile 1@ comprises a shell 15, the forward end thereof beingscrew-threaded as at 16 having engagement with a screw-threaded nipple17 provided on a plug or adapter 1S and thus the plug is secured to theshelly 15 of the projectile. The adapter 18 is provided with ascrewthreaded opening 19 having the axis thereof arranged coaxially withthe axis of the projectile into which a screwt-hreaded extension 21provided on the usual time delay fuze 22 isv threaded, whereby the timenose fuze is secured to the projectile at the leading end thereof. Theshell 15 comprises a rear wall 23 integrally formed therewith in which ascrew-threaded'opening 24 is provided whereby the shell may be lle'dwith an explosive or bursting charge 25. After the shell has been filledwith the explosive bursting charge, a screw-threaded plug 26 i`sthreaded into the opening 24 thus sealing the opening and retaining theexplosive bursting charge within the shell15.

An auxiliary fuze generally indicated by the reference character 27 issecured within the adapter 18 and cornprises a casing 28 having ascrew-threaded portion thereon adapted to have engagement with ascrew-threaded opening 29 provided in the adapter 18 which communicateswith`the opening 19 therein whereby the auxiliary fuze is secured withinthe adapter in proximate spaced rela'- tion with respect to the timefuze 22. The auxiliary fuze 27 isV adapted to extend a predetermineddistance within the bursting charge 25', thus providing means for eX-ploding the burstingV charge within the shell 15 in pre'- determinedtime delayed relation with respect to tiring of the time fuze after theprojectile has been fired from a gun, as will be more clearly apparentas the description proceeds. The casing 23 is provided with a recess 31in one end thereof having a booster charge 32 arranged therein. Thebooster charge is retained within'the re`- cess 31 by a cap 33 adaptedto have screw-threaded engagementV with a reduced screw-threaded nipple34 provided on one end of the casing 28. A cushion disk and moistureproof seal 35 composed of any material suitable for the purpose such,for example, as blotting paper or the like is disposed between the cap33 and the end of the nipple 34, the disk being clamped against thelower end of the nipple and booster charge by the cap 33 in such amanner as to prevent moisture from seeping therethrough and also preventshifting of the booster charge within the recess, and thus prematuretiring of the booster charge due to shifting of the charge duringtransportation handling and when the projectile is red from a gun isprevented. The casing 28 is also provided with a recess or bore 36adapted to extend substantially therethrough, the recess 36 beingseparated from the recess 31 by a partition 37 integrally formed on thecasing 28.

A firing unit generally indicated by the reference character 38 isarranged within the recess or bore 36, one end of which engages theouter surface of the partition 37 and the other end thereof has disposedthereon a moisture proof protector disk 39 composed of any materialsuitable for the purpose such, for example, as oil paper, tin foil orthe like. The firing unit 38 is retained Within the recess 36 by anannular member 41 adapted to have threaded engagement with a threadedportion 42 of the recess or bore 36. The tiring unit 38 is also adaptedto have abutting relation with respect to the protector disk 39 and thusit will be apparent, particularly with reference to Figs. 2, 4 and 5 ofthe drawings, that the ring unit is clamped in a xed position within therecess 36 by the annular member 41 and the disk 39 is employed as a sealto exclude moisture therefrom. The annular member 41 is provided with acentrally disposed opening 40 arranged coaxially with respect to theaxis of the projectile and having a piston or cup 30 slideably arrangedtherein, the purpose of which will be hereinafter more fully described.The annular member 41 is also provided with a pair of recesses 43adapted to provide means whereby a suitable Wrench such, for example, asa spanner wrench may be applied thereto for threading the annular memberinto the threaded portion of the bore 36 thereby compressing the disk 39between ring unit 38 and the annular member.

The ring unit 38 comprises a relatively thin casing or container 44composed of any material suitable for the purpose such, for example, asbrass or the like having enclosed therein a rotor block indicated by thereference character 45, one end thereof being adapted to have abuttingrelation with respect to one end of a firing pin and detent block 46.

Arranged within the casing 44 in abutting relation with respect to theother end of the rotor block 45 is a disk 47 provided with a nipple 48adapted to extend through an opening or bore 49 formed in the partition37. The block 46 and disk 47 are each provided with a recess 51 in whichflange portions 52 respectively provided on each end of the casing 44are adapted to seat whereby the blocks 45 and 46 and the disk 47 aremaintained in fixed abutting relation with respect to each other in sucha manner as to provide a unitary firing mechanism for the projectile.

A rotor or turret 53 composed of any material suitable for the purposesuch, for example, as aluminum having an opening 54 extendingtherethrough, the rotor being arranged within a recess 55 is provided inthe rotor block 45 and adapted to have rotative movement therein. A pairof weights 56 of high specific gravity and composed of any materialsuitable for the purpose such, for example, as lead are arranged indiametrically disposed apertures provided in the rotor 53, in unbalancedrelation with respect to the axis of the fuze when the rotor is in anunarmed position within the recess 55. When the projectile starts torotate as a result of the rotary movement imparted thereto by the riflngof the gun as the projectile is fired therefrom, the weights 56 willtend to move outwardly in response to centrifugal force and will spinthe rotor in an armed position when the projectile has reached themaximum speed of rotation. Arranged within the opening 54 of the rotoris a compound ring unit indicated generally by the reference character57. The firing unit includes a detonator 58 comprising a casing 59having a detonating charge 60 arranged therein. The tiring unit alsoincludes a percussion cap 61 arranged within the opening 54 of the rotorin abutting relation with respect to the detonator casing 59 andcomprises a base member 62 having an anvil 63 formed thereon in abuttingrelation with respect to an explosive cap 64 secured to the base memberin any suitable manner and adapted to re the detonator. The base member62 of the percussion cap is provided with a ash channel 65 incommunication with a bore 66 provided in the casing 59 of the detonatorto provide means whereby a ash or burst of ame from the explosive cap 64when red may enter the flash channel 65 and bore 66 and initiate firingor the detonator charge 60.

It will be understood, however, that means are provided for theprojectile whereby the rotor is prevented from rotating or, in otherwords, the rotor is maintained in a safe or unarmed position duringhandling, transportation, and during loading of the projectile into agun. Such means are clearly shown on the drawings, especially Figs. 5, 6and 9 thereof, and comprise a pair of diametrically disposed releasablelatching members 67, each of the members having a reduced extension orprotuberance 68 formed thereon adapted to seat in a pair of recesses 69,respectively provided on opposite sides of the rotor 53. The members 67are slidcably supported within a pair of cup-shaped members 71respectively arranged in diametrically disposed apertures 72 provided inthe rotor block 45 and each member 67 is adapted to be urged inwardlytoward the rotor 53 by springs 73 respectively arranged in bores 74provided within the rotor block, the springs being in engagement withthe bottom wall of the bore and the upper wall of the cup-shaped member71. Thus the extensions 68 are maintained in engagement with therecesses 69 thereby preventing rotation of the rotor until after theprojectile has been ired from the gun and a predetermined speed ofrotation of the projectile has been reached.

It will be understood, however, that the spring pressed members 67 areadapted to maintain the rotor supporting the compound tiring unit 57 ina safe or unarmed position with respect to a lead-in charge 75 arrangedin an aperture provided in the nipple 48 of the disk 47. The rotor isalso maintained in a safe position with respect to a tiring pin as willhereinafter appear in greater detail as the description proceeds. Therotor supporting the detonator and percussion cap is thus maintained ina safe position as the projectile is fired from a gun by the extensions68 extending into the recesses 69 and will remain in safe position untilthe acceleration of the projectile has reached substantially a zerovalue and the speed of rotation thereof about the axis of the projectilehas reached a predetermined value. When this occurs the extensions 68will be withdrawn from the recesses 69 in the rotor and the rotor willmove to the armed position shown on Figs. 4, 5 and 6 of the drawingswhen the projectile has reached a maximum speed of rotation.v

The blocks 45 are each provided with a pair of bores in registrationwith respect to each other thereby forming a pair of gas and pressurelrelief chambers 70 adapted to relieve the pressure from the expandinggases should the detonator be red prematurely when in an unarmedposition thereby preventing premature detonation of the booster chargeand explosion of the shell.

The rotor is so constructed as to be balanced statically, that is, anytwo parts thereof diametrically opposed and in a plane crossing the axisof the rotor are of equal weight. The specific gravity of the compoundtiring unit, however, is less than the specific gravity of thesurrounding material and the specific gravity of the weights 56 isgreater than the specific gravity of the surrounding material whereby adynamic couple is produced by rotation of the shell suicient to rotatethe rotor into armed position with the compound tiring unit in alinementwith the rotational axis of the projectile after the projectile leavesthe muzzle of the gun.

A firing pin 76 is slideably arranged within the block 46 comprising ahead 77 disposed within a recess 78 formed in the block 46 and alsohaving a reduced shank or hammer member 79 connected thereto extendinginto an aperture 81 also formed in the block 46 and adapted tocommunicate with the recess 55 provided in rotor block 45 therebyproviding means for firing the compound firing unit to initiate firingof the bursting charge within the shell 15 in response to the actuationof the piston by the explosive pressure produced by the time nose fuzeas the nose fuze functions, the movement of the j piston 30 also causingrupture of the seal 39.

The block 46 is also provided with a pair of diametrically arrangedapertures 82 within which are respectively disposed a pair of lockingdetents 83 adapted to be releasably maintained in engagement with theshank 79 of the tiring pin by springs 84 respectively arranged withinrecesses 85 provided in the detents 83, the springs being disposedbetween the bottom wall of the recess and a retaining member 86 securedto the block 46 in any suitable manner, and thus the detents areyieldably and inwardly urged against the shank 79 of the tiring pinwhile the projectile is at rest.

With the detents 83 in locking position as shown on Fig. 1 of thedrawings, the firing pin is maintained locked in safe or unarmedposition and prevented from being brought into contact with thepercussion cap 61 by reason of the engagement of the inner portions ofthe detents with the inner surface or shoulder 87 of the firing pin.

The force resulting from the acceleration of the projectile in responseto the expansion of the gases within the gun is applied in a directionalong the path of travel of the projectile and is well known in theordnance art as a setback force. This setback force decays to zero asthe projectile leaves the muzzle of the gun. Therefore, it will beunderstood that the setback force applied to the ring pin and detentswill tend to bind the detents in the apertures 82 and also tend to bindthe shoulder 87 of the tiring pin against the inner portion of thedetents, thus preventing movement of the detents away from the tiringpin until the setback force has reached substantially a zero value andthe rotation of the projectile has reached a maximum value after theprojectile has passed the limits of the muzzle of the gun.

As the projectile is propelled along the bore of the gun by theexplosion of the charge 14, the riing of the bore engages the sleeve 13and imparts rotative movement of the projectile, thereby causing thedetents 83 to be spun about the axis of the projectile and a centrifugalforce to be generated thereby. It will be understood, however, that thisforce is of sufficient strength to overcome the tension of the springs84 and to cause the detents 83 to move outwardly to an unlocking orarmed position and thus provide a clear path of travel for the ring pin.

On Figs. 4 and 5 of the drawings the rotor is shown moved in an armedposition and the firing pin is unlocked by centrifugal force during thetravel of the projectile along the trajectory. That is to say, inresponse to centrifugal force the latching members 67 are moved out ofthe recesses 69 when the centrifugal force has reached sufficientstrength to overcome the tension of springs 73 whereby the rotor isreleased for movement to an armed position within the recess 55 in therotor block 45 and centrifugal force will also maintain the detents 83in the unlocking or armed position when the force has reached suicientstrength to overcome the tension of the springs 84 arranged therein,thus permitting the detonator and percussion cap to be moved into thepath of travel of the firing pin and unlocking the tiring pinrespectively. Thus the ring pin 76 is in readiness to be driven againstthe explosive cap 64 of the percussion cap 61 by the piston 30 which isoperated by the sudden pressure applied thereto when the time fuzefunctions, as is well known in the art. It will be understood that thetime fuze 22 is of any well known construction and is adapted to supplysucient pressure when operated to force the piston 30 into engagementwith the tiring pin and drive the ring pin against the cap 64 withsuflicient force to explode the cap and initiate firing of the burstingcharge.

As the gun is red the initial movement of the projectile away from theshell casing is a motion of translation and when the projectile hasmoved a predetermined distance within the bore of the gun, the sleeve 13engages the riing of the bore and rotation of the projectile isinitiated thereby, Therefore it will be apparent that the setback forceis applied to the projectile prior to rotative movement thereof and willmaintain the rotor and firing pin in an unarmed position until thesetback force has diminished substantially to zero value and thecentrifugal force has reached a maximum value, thereby providing anarrangement in which there is no possibility of prematurely arming thefuze until the projectile has passed beyond the muzzle of the gun.

In the event, however, that the detonator should be red during theassembly or inspection of the fuze while the rotor supporting thedetonator is in a safe position, substantial injury to the personnelwithin the vicinity of the fuze is prevented by the provision of thepair of pressure relief chambers within the fuze structure.

The many advantages of the auxiliary fuze constructed in accordance withthe present invention will be readily apparent from the foregoingdescription, taken in connection with the accompanying drawings and,although a preferred embodiment of the device is illustrated anddescribed, it is to be understood that changes in the details ofconstruction and in the combination and arrangement of parts may beresorted to which fall within the scope of the invention as claimed.

The invention described herein may be manufactured and used by or forthe Government of the United States of America for governmental purposeswithout the payment of any royalties thereon or therefor.

What is claimed as new and desired to be secured by Letters Patent ofthe United States is:

1. An auxiliary fuze for a high-explosive projectile comprising acasing, a disk arranged within one end of said casing and having alead-in charge arranged therein, a block member arranged within theother end of said casing, a firing pin releasably locked within saidblock member and adapted to have sliding movement therein when released,means for actuating the firing pin, means controlled by centrifugalforce for releasing said firing pin, a rotor block disposed between saiddisk and block member and having a recess therein, retaining meansprovided on each end of said casing in engagement with the disk andblock member respectively for clamping said disk, block member and rotorblock in fixed position within said casing, a rotor releasablymaintained within said recess in a safe position and adapted to haverotative movement therein when released, means controlled by centrifugalforce for releasing said rotor, means responsive to centrifugal forcefor moving said rotor to an armed position after the rotor is released,and a detonator arranged within said rotor and adapted to tire saidlead-in charge while the rotor is in said armed position as thedetonator is fired by the actuation of said firing pin.

2. An auxiliary fuze for a high-explosive projectile comprising acasing, a disk arranged within one end of said casing and having alead-in charge arranged therein, a block member arranged within theother end of said casing, a firing pin releasably locked within saidblock member and adapted to have sliding movement therein when released,means for actuating the tiring pin, means controlled by centrifugalforce for releasing said firing pin, a rotor block disposed between saiddisk and block member and having a recess therein, retaining meansprovided on each end of said casing in engagement with the disk andblock member respectively for clamping the rotor block in fixed positionWithin said casing, said rotor block and block member having a pair ofregistering recessed portions respectively arranged therein to provide apair of pressure relief chambers in communication with said recess, arotor releasably maintained within said recess in a safe position andadapted to have rotative movement therein when released, meanscontrolled by centrifugal force for releasing said rotor, meansresponsive to centrifugal force for moving said rotor to an armedposition after the rotor is released, and a detonator arranged withinsaid rotor and adapted to fire said lead-in charge while the rotor is insaid armed position as the detonator is red by the actuation of saidfiring pin.

3. An auxiliary fuze for a high explosive projectile, comprising acylindrical member having a booster charge arranged therein, means forhermetically sealing said booster charge, a casing disposed within saidcylindrical member, a disk arranged within one end of said casing havinga lead-in charge arranged therein adapted to ire said booster charge, arotor block arranged Within said casing in abutting relation withrespect to said disk and having a recess therein, a block memberarranged within said casing in abutting relation with respect to saidrotor block, ange members provided on each end of said casing inengagement with the disk and block member respectively for clamping saiddisk, rotor block and block member together to provide a unitary firingunit, a rotor releasably maintained within said recess in a safeposition and adapted to have rotative movement therein when released,means controlled by centrifugal force for releasing said rotor, meansresponsive to centrifugal force for moving said rotor to an armedposition after the rotor is released, a detonator arranged within saidrotor and adapted to lire said lead-in charge when said rotor has beenmoved to an armed position and said detonator has been ired, a firingpin releasably locked within the block member and adapted to havesliding movement therein when released, means controlled by centrifugalforce for releasing said firing pin to lire said detonator when therotor has moved the detonator in line with said firing pin, means forhermetically sealing said fuze, said last named means including aretaining member, and means Within said retaining member for actuatingsaid firing pin when the rin'g pin has been released.

References Cited in the file of this patent UNITED STATES PATENTS1,310,046 Asbury July 15, 1919 1,531,716 Remondy Mar. 31, 1925 2,359,752Del Prato Oct. 10, 1944 2,392,430 Teitscheid Jan. 8, 1946 2,392,884Semple Ian. 15, 1946 2,441,939 Nichols May 18, 1948 2,546,999 Graumannet al Apr. 3, 1951 FOREIGN PATENTS 218,586 Great Britain July 10, 1924257,335 Great Britain Aug. 27, 1926 694,402 France Sept. 15, 1930837,467 France Nov. 12, 1938

